Method and apparatus for performing minimally invasive cardiac procedures

ABSTRACT

A system for performing minimally invasive cardiac procedures. The system includes a pair of surgical instruments that are coupled to a pair of robotic arms. The instruments have end effectors that can be manipulated to hold and suture tissue. The robotic arms are coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the end effectors. The movement of the handles is scaled so that the end effectors have a corresponding movement that is different, typically smaller, than the movement performed by the hands of the surgeon. The scale factor is adjustable so that the surgeon can control the resolution of the end effector movement. The movement of the end effector can be controlled by an input button, so that the end effector only moves when the button is depressed by the surgeon. The input button allows the surgeon to adjust the position of the handles without moving the end effector, so that the handles can be moved to a more comfortable position. The system may also have a robotically controlled endoscope which allows the surgeon to remotely view the surgical site. A cardiac procedure can be performed by making small incisions in the patient&#39;s skin and inserting the instruments and endoscope into the patient. The surgeon manipulates the handles and moves the end effectors to perform a cardiac procedure such as a coronary artery bypass graft.

RELATION TO PREVIOUSLY FILED APPLICATIONS

[0001] The present application is a continuation-in-part application ofU.S. patent application entitled “A Method and Apparatus For PerformingMinimally Invasive Cardiac Procedures”, which received Ser. No.08/603,543 and which was filed on Feb. 20, 1996, and which is presentlypending and is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a system and method forperforming minimally invasive cardiac procedures. More particularly, thepresent invention relates to a robotic system and surgical instrumentsthat may be removably attached thereto, wherein said system aids inperforming minimally invasive surgical procedures.

[0004] 2. Description of Related Art

[0005] Blockage of a coronary artery may deprive the heart of the bloodand oxygen required to sustain life. The blockage may be removed withmedication or by an angioplasty. For severe blockage a coronary arterybypass graft (CABG) is performed to bypass the blocked area of theartery. CABG procedures are typically performed by splitting the sternumand pulling open the chest cavity to provide access to the heart. Anincision is made in the artery adjacent to the blocked area. Theinternal mammary artery (IMA) is then severed and attached to the arteryat the point of incision. The IMA bypasses the blocked area of theartery to again provide a full flow of blood to the heart. Splitting thesternum and opening the chest cavity, commonly referred to as ‘opensurgery’, can create a tremendous trauma on the patient. Additionally,the cracked sternum prolongs the recovery period of the patient.

[0006] There have been attempts to perform CABG procedures withoutopening the chest cavity. Minimally invasive procedures are conducted byinserting surgical instruments and an endoscope through small incisionin the skin of the patient. Manipulating such instruments can beawkward, particularly when suturing a graft to a artery. It has beenfound that a high level of dexterity is required to accurately controlthe instruments. Additionally, human hands typically have at least aminimal amount of tremor. The tremor further increases the difficulty ofperforming minimally invasive cardiac procedures.

[0007] To perform MIS, the surgeon uses special instruments. Theseinstruments allow the surgeon to maneuver inside the patient. One typeof instrument that is used in minimally invasive surgery is forceps, aninstrument having a tip specifically configured to grasp objects, suchas needles. Because forceps and other instruments designed for minimallyinvasive surgery are generally long and rigid, they fail to provide asurgeon the dexterity and precision necessary to effectively carry outmany procedures in a minimally invasive fashion. For example,conventional MIS forceps are not well suited for manipulating a needleduring a minimally invasive procedure, such as during endoscopy.Therefore, many MIS procedures that might be performed, have, as of yet,not been accomplished.

[0008] In essence, during open surgeries, the tips of the variousinstruments may be positioned with six degrees of freedom. However, byinserting an instrument through a small aperture, such as one made in apatient to effectuate a minimally invasive procedure, two degrees offreedom are lost. It is this loss of freedom of movement within thesurgical site that has substantially limited the types of MIS proceduresthat are performed.

[0009] Dexterity is lacking in MIS because the instruments that are usedfail to provide the additionally degrees of freedom that are lost whenthe instrument is inserted into a patient. One problem associated withthis lack of dexterity is the inability to suture when the instrumentsare in certain positions. As a result, surgeries that require a greatdeal of suturing within the surgical site are almost impossible toperform because the surgical instruments to enable much of this work arenot available.

[0010] Another problem associated with MIS is the lack of precisionwithin the surgical site. For procedures such as the MICABG (MinimallyInvasive Coronary Artery Bypass Graft), extremely, small sutures must beemplaced in various locations proximate the heart. As such, precisemotion of the tool at the tip of a surgical instrument is necessary.Currently, with hand positioned instruments, the precision necessary forsuch suturing is lacking.

[0011] As such, what is needed in the art is a tool and class ofsurgical instruments that may be articulated within the patient suchthat a surgeon has additional degrees of freedom available to moredexterously and precisely position the tool at the tip of theinstrument, as is needed.

[0012] Additionally, what is needed in the art is a method and mechanismthat provides simple instrument and tool changing capabilities so thatvarious tools may be easily and readily replaced to enable fasterprocedures to thus minimize operating room costs to the patient and tolessen the amount of time a patient is under anesthesia.

[0013] It is to the solution of the aforementioned problems to which thepresent invention is directed.

SUMMARY OF THE INVENTION

[0014] The present invention is a system for performing minimallyinvasive cardiac procedures. The system includes a pair or more ofsurgical instruments that are coupled to a pair or more of robotic arms.The system may include only a single surgical instrument and a singlerobotic arm as well and as is hereinbelow disclosed. The instrumentshave end effectors that can be manipulated to sever, hold, cauterize andsuture tissue. The robotic arms are coupled to a pair of master handlesby a controller. The handles can be moved by the surgeon to produce acorresponding movement of the end effectors. The movement of the handlesis scaled so that the end effectors have a corresponding movement thatis different, typically smaller, than the movement performed by thehands of the surgeon. This helps in removing any tremor the surgeonmight have in their hands. The scale factor is adjustable so that thesurgeon can control the resolution of the end effector movement. Themovement of the end effector can be controlled by an input button, sothat the end effector only moves when the button is depressed or toggledby the surgeon. The input button allows the surgeon to adjust theposition of the handles without moving the end effector, so that thehandles can be moved to a more comfortable position. The system may alsohave a robotically controlled endoscope which allows the surgeon toremotely view the surgical site. A cardiac procedure can be performed bymaking small incisions in the patient's skin and inserting theinstruments and endoscope into the patient. The surgeon manipulates thehandles and moves the end effectors to perform a cardiac procedure suchas a coronary artery bypass graft or heart valve surgery.

[0015] The present invention is additionally directed to a surgicalinstrument and method of control thereof which permits the surgeon toarticulate the tip of the instrument, while retaining the function ofthe tool at the tip of the instrument. As such, the instrument tip maybe articulated with two degrees of freedom, all the while the tooldisposed at the tip may be used.

[0016] The robotic system generally comprises:

[0017] a robotic arm;

[0018] a coupler that attached to the arm;

[0019] a surgical instrument that is held by the coupler;

[0020] a controller; and

[0021] wherein movement at the controller produces a proportionalmovement of the robotic arm and surgical instrument.

[0022] The present invention may include a surgical instrument that hasan elongated rod. The elongated rod has a longitudinal axis andgenerally serves as the arm of the endoscopic instrument. An articulateportion is mounted to and extends beyond the elongated rod.Alternatively, the articulate portion may be integrally formed with theelongated rod. The articulate portion has a proximal portion, a pivotlinkage and a distal portion. The proximal portion may include a pair offingers. The fingers may be orthogonal to each other and orientedradially to the longitudinal axis of the elongated rod. For use insurgical procedures, it is generally preferable that the instrument andthe majority of the components therein are formed of stainless steel,plastic, or some other easily steralizable material. Each of the fingersmay have at least one aperture formed therein to allow the passage of apin which aids in the attachment of the pivot linkage to the proximalportion of the articulate portion and which allows the pivot linkage tobe pivotally mounted to the proximal portion. The articulate portionprovides articulation at the tip of an instrument that includes thearticulate portion. More particularly, this provides additional degreesof freedom for the tool at the tip of an instrument that includes anarticulate portion.

[0023] An instrument such as that disclosed hereinbelow, when used inconjunction with the present surgical system, provides the surgeonadditional dexterity, precision, and flexibility not yet achieved inminimally invasive surgical procedures. As such, operation times may beshortened and patient trauma greatly reduced.

[0024] To provide increased precision in positioning the articulated tipas disclosed hereinbelow, there is provided two additional degrees offreedom to the master controller. Each of the two additional degrees offreedom are mapped to each of the degrees of freedom at the instrumenttip. This is accomplished through the addition of two joints on themaster and automatic means for articulating the instrument tip inresponse to movements made at the master.

[0025] The objects and advantages of the present invention will becomemore readily apparent to those ordinarily skilled in the art afterreviewing the following detailed description and drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a perspective view of a minimally invasive surgicalsystem in accordance with the present invention;

[0027]FIG. 2 is a schematic of a master of the system;

[0028]FIG. 3 is a schematic of a slave of the system;

[0029]FIG. 4 is a schematic of a control system of the system;

[0030]FIG. 5 is a schematic showing the instrument in a coordinateframe;

[0031]FIG. 6 is a schematic of the instrument moving about a pivotpoint;

[0032]FIG. 7 is an exploded view of an end effector in accordance withthe system of the present invention;

[0033]FIG. 8 is a view of a master handle of the system in accordancewith the present invention;

[0034]FIG. 8a is a side view of the master handle of the system inaccordance with the present invention;

[0035] FIGS. 9-10A-J are illustrations showing an internal mammaryartery being grafted to a coronary artery;

[0036]FIG. 11 is a side view of a rear-loading tool driver in accordancewith the system of the present invention;

[0037]FIG. 12 is a plan view of the motor assembly of the back loadingtool driver of FIG. 11;

[0038]FIG. 13 is a side plan view of an articulable instrument inaccordance with the present invention;

[0039]FIG. 14 is a side plan view of an articulable instrument, wherethe instrument tip is articulated;

[0040]FIG. 15 is an exploded view of the articulable portion of thearticulable instrument in accordance with the present invention;

[0041]FIG. 16 is a plan view of a pivot linkage in accordance with thearticulate portion of the articulable surgical instrument of the presentinvention;

[0042]FIG. 17 is a perspective view of an articulating tool drivingassembly in accordance with the present invention;

[0043]FIG. 18 is a view of a removable tool-tip in accordance with anarticulable instrument of the present invention;

[0044]FIG. 19 is a tool-tip receptacle in accordance with the presentinvention;

[0045]FIG. 20 is a cross-sectional view of an articulable instrumentattached to the articulate-translator of the present invention;

[0046]FIG. 21 is a close-up cross section view of thearticulate-translator in accordance with the present invention;

[0047]FIG. 22 is an end view of the articulate translator in accordancewith the present invention;

[0048]FIG. 23 is a cross-sectional view of the sterile section of thearticulating tool driving assembly in accordance with the system of thepresent invention;

[0049]FIG. 24 is a cross sectional view of the tool driver of thearticulating tool driving assembly in accordance with the system of thepresent invention;

[0050]FIG. 25 is an schematic of a master of a system in accordance withthe present invention that includes the articulating tool drivingassembly;

[0051]FIG. 26 is a plan view of a drape for use with the robotic arm inaccordance with the present invention;

[0052]FIG. 27 is a plan view of a surgical instrument having a staplingtool disposed at the end thereof and wherein the surgical instrument isattached to the robotic arm in accordance with the present invention;

[0053]FIG. 28 is a plan view of a surgical instrument having a cuttingblade disposed at the end thereof wherein the instrument is attached tothe robotic arm in accordance with the present invention;

[0054]FIG. 29 is a plan view of a surgical instrument having acoagulating/cutting device disposed at the end thereof, the instrumentattached to a robotic arm in accordance with the present invention; and

[0055]FIG. 30 is a plan view of a surgical instrument having a suturingtool disposed at the end thereof and wherein the surgical instrument isattached to the robotic arm in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0056] Referring to the drawings more particularly by reference numbers,FIG. 1 shows a system 10 that can be used to perform minimally invasivesurgery. In a preferred embodiment, the system 10 may be used to performa minimally invasive coronary artery bypass graft, or Endoscopiccoronary artery bypass graft (E-CABG) and other anastomostic procedures.Although a MI-CABG procedure is shown and described, it is to beunderstood that the system may be used for other surgical procedures.For example, the system can be used to suture any pair of vessels.

[0057] The system 10 is used to perform a procedure on a patient 12 thatis typically lying on an operating table 14. Mounted to the operatingtable 14 is a first articulate arm 16, a second articulate arm 18 and athird articulate arm 20. The articulate arms 16-20 are preferablymounted to the table so that the arms are at a same reference plane asthe patient. It is to be appreciated that the arms may be mounted to acart or some other device that places the arms proximate the plane ofthe patient as well. Although three articulate arms are shown anddescribed, it is to be understood that the system may have any number ofarms, such as one or more arms.

[0058] The first and second articulate arms 16 and 18 each have a basehousing 25 and a robotic arm assembly 26 extending from the base housing25. Surgical instruments 22 and 24 are preferably removably coupled atthe end of each robotic arm assembly 26 of the first and secondarticulate arms 16, 18. Each of the instruments 22, 24 may be coupled toa corresponding robotic arm assembly 26 in a variety of fashions whichwill be discussed in further detail hereinbelow.

[0059] The third articulate arm 20 additionally comprises a base housing25 and a robotic arm assembly 26, and preferably has an endoscope 28that is attached to the robotic arm assembly 26. The base housing 25 androbotic arm assemblies 26 of each of the articulate arms 16, 18, and 20are substantially similar. However, it is to be appreciated that theconfiguration of the third articulate arm 20, may be different as thepurpose of the third articulate arm is to hold and position theendoscope 28 as opposed to hold and position a surgical instrument.

[0060] The instruments 22 and 24, and endoscope 28 are inserted throughincisions cut into the skin of the patient 12. The endoscope 28 has acamera 30 that is coupled to a monitor 32 which displays images of theinternal organs of the patient 12.

[0061] Each robotic arm assembly 26 has a base motor 34 which moves thearm assembly 26 in a linear fashion, relative to the base housing 25, asindicated by arrows Q. Each robotic arm assembly 26 also includes afirst rotary motor 36 and a second rotary motor 38. Each of the roboticarm assemblies 26 also have a pair of passive joints 40 and 42. Thepassive joints 40, 42 are preferably disposed orthogonal to each otherto provide pivotal movement of the instrument 22, 24 or endoscope 28that is attached to a corresponding robotic arm assembly 26. The passivejoints may be spring biased in any specific direction, however, they arenot actively motor driven. The joint angle is controlled to a particularvalue using a feedback control loop. The robotic arm assemblies 26 alsohave a coupling mechanism 45 to couple the instruments 22 and 24, orendoscope 28 thereto. Additionally, each of the robotic arm assemblies26 has a motor driven worm gear 44 to rotate the instrument 22, 24 orendoscope 28 attached thereto about its longitudinal axis. Moreparticularly, the motor driven worm gear spins the instruments orendoscope.

[0062] The first, second, and third articulate arms 16, 18, 20 arecoupled to a controller 46 which can control the movement of the arms.The arms are coupled to the controller 46 via wiring, cabling, or via atransmitter/receiver system such that control signals may be passed formthe controller 46 to each of the articulate arms 16, 18, and 20. It ispreferable, to ensure error free communication between each of thearticulate arms 16, 18 and 20 and the controller 46 that each arm 16,18, 20 be electrically connected to the controller, and for the purposesof example, each arm 16, 18, 20 is electrically connected to thecontroller 46 via electrical cabling 47. However, it is possible tocontrol each of the arm 16, 18, 20 remotely utilizing well-known remotecontrol systems as opposed to direct electrical connections. As suchremote control systems are well-known in the art, they will not befurther discussed herein.

[0063] The controller 46 is connected to an input device 48 such as afoot pedal, hand controller, or voice recognition unit. For purposes ofexample, a foot controller is disclosed herein. The input device 48 canbe operated by a surgeon to move the location of the endoscope 28 andview a different portion of the patient by depressing a correspondingbutton(s) disposed on the input device 48. The controller 46 receivesthe input signals from the input device 48 and moves the endoscope 28and robotic arm assembly 26 of the third articulate arm 20 in accordancewith the input commands of the surgeon. Each of the robotic armassemblies 26 may be devices that are sold by the assignee of thepresent invention, Computer Motion, Inc. of Goleta, Calif., under thetrademark AESOP. The system is also described in U.S. Pat. No.5,515,478, which is hereby incorporated by reference. Although a footpedal 49 is shown and described, it is to be understood that the systemmay have other input means such as a hand controller, or a speechrecognition interface.

[0064] The movement and positioning of instruments 22, 24 attached tothe first and second articulate arms 16 and 18 is controlled by asurgeon at a pair of master handles 50 and 52. Each of the masterhandles 50, 52 which can be manipulated by the surgeon, has amaster-slave relationship with a corresponding one of the articulatearms 16, 18 so that movement of a handle 50 or 52 produces acorresponding movement of the surgical instrument 22, 24 attached to thearticulate arm 16, 18.

[0065] The handles 50 and 52 may be mounted to a portable cabinet 54. Asecond television monitor 56 may be placed onto the cabinet 54 andcoupled to the endoscope 28 via well-known means so that the surgeon canreadily view the internal organs of the patient 12. The handles 50 and52 are also coupled to the controller 46. The controller 46 receivesinput signals from the handles 50 and 52, computes a correspondingmovement of the surgical instruments, and provides output signals tomove the robotic arm assemblies 26 and instruments 22, 24. Because thesurgeon may control the movement and orientation of the instruments 22,24 without actually holding the ends of the instruments, the surgeon mayuse the system 10 of the present invention both seated or standing. Oneadvantage of the present system is that a surgeon may perform endoscopicsurgeries in a sitting position. This helps reduce surgeon fatigue andmay improve performance and outcomes in the operating room, especiallyduring those procedures that are many hours in length. To accommodate aseated position, a chair 57 may be provided with the system.

[0066] Each handle has multiple degrees of freedom provided by thevarious joints Jm1-Jm5 depicted in FIG. 2. Joints Jm1 and Jm2 allow thehandle to rotate about a pivot point in the cabinet 54. Joint Jm3 allowsthe surgeon to move the handle into and out of the cabinet 54 in alinear manner. Joint Jm4 allows the surgeon to rotate the master handleabout a longitudinal axis of the handle. The joint Jm5 allows a surgeonto open and close a gripper.

[0067] Each joint Jm1-Jm5 has one or more position sensors whichprovides feedback signals that correspond to the relative position ofthe handle. The position sensors may be potentiometers, or any otherfeedback device such as rotary optical encoders that provides anelectrical signal which corresponds to a change of position.Additionally, a plurality of position sensors may be emplaced at eachjoint to provide redundancy in the system which can be used to alert asurgeon of malfunctions or improper positioning of a correspondingrobotic arm assembly 26.

[0068] In addition to position sensors, each joint may includetachometers, accelerometers, and force sensing load cells, each of whichmay provide electrical signals relating to velocity, acceleration andforce being applied at a respective joint. Additionally, actuators maybe included at each joint to reflect force feed back received at arobotic arm assembly 26. This may be especially helpful at joint jm5 toindicate the force encountered inside a patient by the gripper disposedat the end of one of the tools 22, or 24. As such, a force reflectiveelement must be included at the gripper of the instrument 22, 24 toeffectuate such a force reflective feedback loop. Force reflectiveelements, such as a piezoelectric element in combination with awhetstone bridge are well-known in the art. However, it is notheretofore know to utilize such force reflection with such a system 10.

[0069]FIG. 3 shows the various degrees of freedom of each articulate arm16 and 18. The joints Js1, Js2 and Js3 correspond to the axes ofmovement of the base motor 34 and rotary motors 36, 38 of the roboticarm assemblies 26, respectively. The joints Js4 and Js5 correspond tothe passive joints 40 and 42 of the arms 26. The joint Js6 may be amotor which rotates the surgical instruments about the longitudinal axisof the instrument. The joint Js7 may be a pair of fingers that can openand close. The instruments 22 and 24 move about a pivot point P locatedat the incision of the patient.

[0070]FIG. 4 shows a schematic of a control system that translates amovement of a master handle into a corresponding movement of a surgicalinstrument. In accordance with the control system shown in FIG. 4, thecontroller 46 computes output signals for the articulate arms so thatthe surgical instrument moves in conjunction with the movement of thehandle. Each handle may have an input button 58 which enables theinstrument to move with the handle. When the input button 58 isdepressed the surgical instrument follows the movement of the handle.When the button 58 is released the instrument does not track themovement of the handle. In this manner the surgeon can adjust or“ratchet” the position of the handle without creating a correspondingundesirable movement of the instrument. The “ratchet” feature allows thesurgeon to continuously move the handles to more desirable positionswithout altering the positions of the arms. Additionally, because thehandles are constrained by a pivot point the ratchet feature allows thesurgeon to move the instruments beyond the dimensional limitations ofthe handles. Although an input button 58 is shown and described, it isto be understood that the surgical instrument may be activated by othermeans such as voice recognition. The input button may alternatively belatched so that movement of the corresponding instrument toggles betweenactive and inactive each time the button is depressed by the surgeon.

[0071] When the surgeon moves a handle, the position sensors providefeedback signals M1-M5 that correspond to the movement of the jointsJm1-Jm5, respectively. The controller 46 computes the difference betweenthe new handle position and the original handle position in computationblock 60 to generate incremental position values _M1-_M5.

[0072] The incremental position values _M1-_M5 are multiplied by scalefactors S1-S5, respectively in block 62. The scale factors are typicallyset at less than one so that the movement of the instrument is less thanthe movement of the handle. In this manner the surgeon can produce veryfine movements of the instruments with relatively coarse movements ofthe handles. The scale factors S1-S5 are variable so that the surgeoncan vary the resolution of instrument movement. Each scale factor ispreferably individually variable so that the surgeon can more finelycontrol the instrument in certain directions. By way of example, bysetting one of the scale factors at zero the surgeon can prevent theinstrument from moving in one direction. This may be advantageous if thesurgeon does not want the surgical instrument to contact an organ orcertain tissue located in a certain direction relative to the patient.Although scale factors smaller than a unit one are described, it is tobe understood that a scale factor may be greater than one. For example,it may be desirable to spin the instrument at a greater rate than acorresponding spin of the handle.

[0073] The controller 46 adds the incremental values _M1-_M5 to theinitial joint angles Mj1-Mj5 in adder element 64 to provide valuesMr1-Mr5. The controller 46 then computes desired slave vectorcalculations in computation block 66 in accordance with the followingequations.

Rdx=Mr3·sin(Mr1)·cos(Mr2)+Px

Rdy=Mr3·sin(Mr1)·sin(Mr2)+Py

Rdz=Mr3·cos(Mr1)+Pz

Sdr=Mr4

Sdg=Mr5

[0074] where;

[0075] Rdx,y,z=the new desired position of the end effector of theinstrument.

[0076] Sdr=the angular rotation of the instrument about the instrumentlongitudinal axis.

[0077] Sdg=the amount of movement of the instrument fingers.

[0078] Px,y,z=the position of the pivot point P.

[0079] The controller 46 then computes the movement of the robotic arm26 in computational block 68 in accordance with the following equations.$\begin{matrix}{{Jsd1} = {Rdz}} \\{{Jsd3} = {\pi - {\cos^{- 1}\left\lbrack \frac{{Rdx}^{2} + {Rdy}^{2} - {L1}^{2} - {L2}^{2}}{2{{L1} \cdot {L2}}} \right\rbrack}}} \\{{Jsd2} = {{{\tan^{- 1}\left( {{Rdy}/{Rdx}} \right)} + {\Delta \quad {for}\quad {Jsd3}}} \leq \quad 0}} \\{{Jsd2} = {{{\tan^{- 1}\left( {{Rdy}/{Rdx}} \right)} - {\Delta \quad {for}\quad {Jsd3}}} > 0}} \\{\Delta = {\cos^{- 1}\left\lbrack \frac{{Rdx}^{2} + {Rdy}^{2} - {L1}^{2} - {L2}^{2}}{{2 \cdot {L1}}\sqrt{{Rdx}^{2} + {Rdy}^{2}}} \right\rbrack}} \\{{Jsd6} = {Mr4}} \\{{Jsd7} = {Mr5}}\end{matrix}$

[0080] where;

[0081] Jsd1=the movement of the linear motor.

[0082] Jsd2=the movement of the first rotary motor.

[0083] Jsd3=the movement of the second rotary motor.

[0084] Jsd6=the movement of the rotational motor.

[0085] Jsd7=the movement of the gripper.

[0086] L1=the length of the linkage arm between the first rotary motorand the second rotary motor.

[0087] L2=the length of the linkage arm between the second rotary motorand the passive joints.

[0088] The controller provides output signals to the motors to move thearm and instrument in the desired location in block 70. This process isrepeated for each movement of the handle.

[0089] The master handle will have a different spatial position relativeto the surgical instrument if the surgeon releases, or toggles, theinput button and moves the handle. When the input button 58 is initiallydepressed, the controller 46 computes initial joint angles Mj1-Mj5 incomputational block 72 with the following equations.

Mj1=tan⁻¹(ty/tx)

Mj2=tan⁻¹(d/tz)

Mj3=D

Mj4=Js6

Mj5=Js7

d={square root}{square root over (tx²+ty²)}${tx} = {{\frac{{Rsx} - {Px}}{D}\quad {ty}} = {{\frac{{Rsy} - {Py}}{D}\quad {tz}} = \frac{{Rsz} - {Pz}}{D}}}$

 D={overscore ()(Rsx−Px)²+(Rsy−Py)²+(Rsz−Pz)²)}

[0090] The forward kinematic values are computed in block 74 with thefollowing equations.

Rsx=L1·cos(Js2)+L2·cos(Js2+Js3)

Rsy=L1·cos(Js2)+L2·sin(Js2+Js3)

Rsz=J1

[0091] The joint angles Mj are provided to adder 64. The pivot pointsPx, Py and Pz are computed in computational block 76 as follows. Thepivot point is calculated by initially determining the original positionof the intersection of the end effector and the instrument PO, and theunit vector Uo which has the same orientation as the instrument. Theposition P(x, y, z) values can be derived from various position sensorsof the robotic arm. Referring to FIG. 5 the instrument is within a firstcoordinate frame (x, y, z) which has the angles θ4 and θ5. The unitvector Uo is computed by the transformation matrix:${Uo} = {\begin{bmatrix}{\cos \quad \Theta_{5}} & 0 & {{- \sin}\quad \Theta_{5}} \\{{- \sin}\quad \Theta_{4}\sin \quad \Theta_{5}} & {\cos \quad \Theta_{4}} & {{- \sin}\quad \Theta_{4}\cos \quad \Theta_{5}} \\{\cos \quad \Theta_{4}\sin \quad \Theta_{5}} & {\sin \quad \Theta_{4}} & {\cos \quad \Theta_{4}}\end{bmatrix}\begin{bmatrix}0 \\0 \\{- 1}\end{bmatrix}}$

[0092] After each movement of the end effector an angular movement ofthe instrument ΔΘ is computed by taking the arcsin of the cross-productof the first and second unit vectors Uo and U1 of the instrument inaccordance with the following line equations Lo and L1.

Δθ=arcsin(|T|)

T=Uo×U1

[0093] where;

[0094] T=a vector which is a cross-product of unit vectors Uo and U1.

[0095] The unit vector of the new instrument position U1 is againdetermined using the position sensors and the transformation matrixdescribed above. If the angle Δθ is greater than a threshold value, thena new pivot point is calculated and Uo is set to U1. As shown in FIG. 6,the first and second instrument orientations can be defined by the lineequations Lo and L1:

[0096] Lo:

xo=M _(x)0·Zo+Cxo

yo=M _(y) o·Zo+Cyo

[0097] L1:

x1=Mx1·Z1+Cx1

y1=My1·Z1+Cy1

[0098] where;

[0099] Zo=a Z coordinate along the line Lo relative to the z axis of thefirst coordinate system.

[0100] Z1=a Z coordinate along the line L1 relative to the z axis of thefirst coordinate system.

[0101] Mxo=a slope of the line Lo as a function of Zo.

[0102] Myo=a slope of the line Lo as a function of Zo.

[0103] Mx1=a slope of the line L1 as a function of Z1.

[0104] My1=a slope of the line L1 as a function of Z1.

[0105] Cxo=a constant which represents the intersection of the line Loand the x axis of the first coordinate system.

[0106] Cyo=a constant which represents the intersection of the line Loand the y axis of the first coordinate system.

[0107] Cx1=a constant which represents the intersection of the L1 andthe x axis of the first coordinate system.

[0108] Cy1=a constant which represents the intersection of the line L1and the y axis of the first coordinate system.

[0109] The slopes are computed using the following algorithms:

Mxo=Uxo/Uzo

Myo=Uyo/Uzo

Mx1=Ux1/Uz1

My1=Uy1/Uz1

Cx0=Pox−Mx1·Poz

Cy0=Poy−My1·Poz

Cx1=P1x−Mx1·P1z

Cy1=P1y−My1·P1z

[0110] where;

[0111] Uo(x, y and z)=the unit vectors of the instrument in the firstposition within the first coordinate system.

[0112] U1(x, y and z)=the unit vectors of the instrument in the secondposition within the first coordinate system.

[0113] Po(x, y and z)=the coordinates of the intersection of the endeffector and the instrument in the first position within the firstcoordinate system.

[0114] P1(x, y and z)=the coordinates of the intersection of the endeffector and the instrument in the second position within the firstcoordinate system.

[0115] To find an approximate pivot point location, the pivot points ofthe instrument in the first orientation Lo (pivot point Ro) and in thesecond orientation L1 (pivot point R1) are determined, and the distancehalf way between the two points Ro and R1 is computed and stored as thepivot point R_(ave) of the instrument. The pivot point R_(ave) isdetermined by using the cross-product vector T.

[0116] To find the points Ro and R1 the following equalities are set todefine a line with the same orientation as the vector T that passesthrough both Lo and L1.

tx=Tx/Tz

ty=Ty/Tz

[0117] where;

[0118] tx=the slope of a line defined by vector T relative to the Z-xplane of the first coordinate system.

[0119] ty=the slope of a line defined by vector T relative to the Z-yplane of the first coordinate system.

[0120] Tx=the x component of the vector T.

[0121] Ty=the y component of the vector T.

[0122] Tz=the z component of the vector T.

[0123] Picking two points to determine the slopes Tx, Ty and Tz (eg.Tx=x1−xo, Ty=y1−yo and Tz=z1−z0) and substituting the line equations Loand L1, provides a solution for the point coordinates for Ro (xo, yo,zo) and R1 (x1, y1, z1) as follows.

zo=((Mx1−tx)z1+Cx1−Cxo)/(Mxo−tx)

z1=((Cy1−Cyo)(Mxo−tx)−(Cx1−Cxo)(Myo−ty))/((Myo−ty)(Mx1−tx)−(My1−ty)(Mxo−tx))

yo=Myo·zo+Cyo

y1=My1·z1+Cy1

xo=Mxo·zo+Cxo

x1=Mx1·z1+Cx1

[0124] The average distance between the pivot points Ro and R1 iscomputed with the following equation and stored as the pivot point ofthe instrument.

R _(ave)=((x1+xo)/2,(y1+yo)/2,(z1+zo)/2

[0125] The pivot point can be continually updated with the abovedescribed algorithm routine. Any movement of the pivot point can becompared to a threshold value and a warning signal can be issued or therobotic system can become disengaged if the pivot point moves beyond aset limit. The comparison with a set limit may be useful in determiningwhether the patient is being moved, or the instrument is beingmanipulated outside of the patient, situations which may result ininjury to the patient or the occupants of the operating room.

[0126] To provide feedback to the surgeon the fingers of the instrumentsmay have pressure sensors that sense the reacting force provided by theobject being grasped by the end effector. Referring to FIG. 4, thecontroller 46 receives the pressure sensor signals Fs and generatescorresponding signals Cm in block 78 that are provided to an actuatorlocated within the handle. The actuator provides a correspondingpressure on the handle which is transmitted to the surgeon's hand. Thepressure feedback allows the surgeon to sense the pressure being appliedby the instrument. As an alternate embodiment, the handle may be coupledto the end effector fingers by a mechanical cable that directlytransfers the grasping force of the fingers to the hands of the surgeon.

[0127]FIG. 7 shows a preferred embodiment of an end effector 80 that maybe used in the present invention. The end effector 80 includes asurgical instrument 82, such as those disclosed hereinabove 22, 24, thatis coupled to a front loading tool driver 84. The end effector 80 ismounted to one of the robotic arm assemblies 26 by coupling mechanism45. The coupling mechanism 45 includes a collar 85 that removablyattaches to a holder 86. The holder 86 includes a worm gear 87 that isdriven by a motor in the robotic arm assembly 26 to rotate the collar 85and in turn rotate the instrument 82 about its longitudinal axis. Theholder 86 includes a shaft 88 that seats into a slot in the robotic armassembly 26. The shaft 88 may be turned by the motor in the armassembly, which then rotates the worm gear 87 thus rotating the collar86 and the instrument 82. A tightening tool 89 may be employed totighten and loosen the collar about the instrument 82. Such a tooloperates like a chuck key, to tighten and loosen the collar 86.

[0128] The surgical instrument 82 has a first finger 90 that ispivotally connected to a second finger 91. The fingers 90, 91 can bemanipulated to hold objects such as tissue or a suturing needle. Theinner surface of the fingers may have a texture to increase the frictionand grasping ability of the instrument 82. The first finger 90 iscoupled to a rod 92 that extends through a center channel 94 of theinstrument 82. The instrument 82 may have an outer sleeve 96 whichcooperates with a spring biased ball quick disconnect fastener 98. Thequick disconnect 98 allows instruments other than the finger grasper tobe coupled to front loading tool driver 84. For example, the instrument82 may be decoupled from the quick disconnect 98 and replaced by acutting tool, a suturing tool, a stapling tool adapted for use in thissystem, such as the stapling apparatus disclosed in U.S. Pat. No.5,499,990 or 5,389,103 assigned to Karlsruhe, a cutting blade, or othersurgical tools used in minimally invasive surgery. The quick disconnect98 allows the surgical instruments to be interchanged without having tore-sterilize the front loading tool driver 84 each time an instrument isplugged into the tool driver 84. The operation of the front loading tooldriver 84 shall be discussed in further detail hereinbelow.

[0129] The quick disconnect 98 has a slot 100 that receives a pin 102 ofthe front loading tool driver 84. The pin 102 locks the quick disconnect98 to the front loading tool driver 100. The pin 102 can be released bydepressing a spring biased lever 104. The quick disconnect 98 has apiston 106 that is attached to the tool rod 92 and in abutment with anoutput piston 108 of a load cell 110 located within the front loadingtool driver 84.

[0130] The load cell 110 is mounted to a lead screw nut 112. The leadscrew nut 112 is coupled to a lead screw 114 that extends from a gearbox 116. The gear box 116 is driven by a reversible motor 118 that iscoupled to an encoder 120. The entire end effector 80 is rotated by themotor driven worm gear 87.

[0131] In operation, the motor 118 of the front loading tool driver 84receives input commands from the controller 46 via electrical wiring, ora transmitter/receiver system and activates, accordingly. The motor 118rotates the lead screw 114 which moves the lead screw nut 112 and loadcell 110 in a linear manner. Movement of the load cell 110 drives thecoupler piston 106 and tool rod 92, which rotate the first finger 88.The load cell 110 senses the counteractive force being applied to thefingers and provides a corresponding feedback signal to the controller46.

[0132] The front loading tool driver 84 may be covered with a steriledrape 124 so that the tool driver 84 does not have to be sterilizedafter each surgical procedure. Additionally, the robotic arm assembly 26is preferably covered with a sterile drape 125 so that it does not haveto be sterilized either. The drapes 124, 125 serve substantially as ameans for enclosing the front loading tool driver 84 and robotic armassembly 26. The drape 125 used to enclose the robotic arm assembly 26is depicted in further detail in FIG. 26. The drape 125 has asubstantially open end 300 wherein the robotic arm assembly 26 may beemplaced into the drape 125. The drape 125 additionally includes asubstantially tapered enclosed end 302 that effectively separates thearm assembly 26 from the operating room environment. A washer 304 havinga small aperture 306 formed therethrough allows an instrument to becoupled to the arm assembly 26 via the coupling mechanism 45. The washer304 reinforces the drape 125 to ensure that the drape 125 does not tearas the arm assembly 26 moves about. Essentially, the instrument cannotbe enclosed in the drape 125 because it is to be inserted into thepatient 12. The drape 125 also includes a plurality of tape 308 havingadhesive 310 disposed thereon. At least one piece of tape 308 isopposedly arranged the other pieces of tape 308 to effectuate theclosing of the drape 125 about the arm assembly 26.

[0133]FIGS. 8 and 8a show a preferred embodiment of a master handleassembly 130. The master handle assembly 130 includes a master handle132 that is coupled to an arm 134. The master handle 132 may be coupledto the arm 134 by a pin 136 that is inserted into a corresponding slot138 in the handle 132. The handle 132 has a control button 140 that canbe depressed by the surgeon. The control button 140 is coupled to aswitch 142 by a shaft 144. The control button 140 corresponds to theinput button 58 shown in FIG. 4, and activates the movement of the endeffector.

[0134] The master handle 132 has a first gripper 146 that is pivotallyconnected to a second stationary gripper 148. Rotation of the firstgripper 146 creates a corresponding linear movement of a handle shaft150. The handle shaft 150 moves a gripper shaft 152 that is coupled aload cell 154 by a bearing 156. The load cell 154 senses the amount ofpressure being applied thereto and provides an input signal to thecontroller 46. The controller 46 then provides an output signal to movethe fingers of the end effector.

[0135] The load cell 154 is mounted to a lead screw nut 158 that iscoupled to a lead screw 160. The lead screw 160 extends from a reductionbox 162 that is coupled to a motor 164 which has an encoder 166. Thecontroller 46 of the system receives the feedback signal of the loadcell 110 in the end effector and provides a corresponding command signalto the motor to move the lead screw 160 and apply a pressure on thegripper so that the surgeon receives feedback relating to the forcebeing applied by the end effector. In this manner the surgeon has a“feel” for operating the end effector.

[0136] The handle is attached to a swivel housing 168 that rotates aboutbearing 170. The swivel housing 168 is coupled to a position sensor 172by a gear assembly 174. The position sensor 172 may be a potentiometerwhich provides feedback signals to the controller 46 that correspond tothe relative position of the handle. Additionally, an optical encodermay be employed for this purpose. Alternatively, both a potentiometerand an optical encoder may be used to provide redundancy in the system.The swivel movement is translated to a corresponding spin of the endeffector by the controller and robotic arm assembly.

[0137] The arm 134 may be coupled to a linear bearing 176 andcorresponding position sensor 178 which allow and sense linear movementof the handle. The linear movement of the handle is translated into acorresponding linear movement of the end effector by the controller androbotic arm assembly. The arm can pivot about bearings 180, and besensed by position sensor 182 located in a stand 184. The stand 184 canrotate about bearing 186 which has a corresponding position sensor 188.The arm rotation is translated into corresponding pivot movement of theend effector by the controller and robotic arm assembly.

[0138] A human hand will have a natural tremor typically resonatingbetween 6-12 hertz. To eliminate tracking movement of the surgicalinstruments with the hand tremor, the system may have a filter thatfilters out any movement of the handles that occurs within the tremorfrequency bandwidth. Referring to FIG. 4, the filter 184 may filteranalog signals provided by the potentiometers in a frequency rangebetween 6-12 hertz. Alternatively, an optical encoder and digital filtermay be used for this purpose.

[0139] As shown in FIGS. 9 and 10A-J, the system is preferably used toperform a cardiac procedure such as a coronary artery bypass graft(CABG). The procedure is performed by initially cutting three incisionsin the patient and inserting the surgical instruments 22 and 24, and theendoscope 26 through the incisions. One of the surgical instruments 22holds a suturing needle and accompanying thread when inserted into thechest cavity of the patient. If the artery is to be grafted with asecondary vessel, such as a saphenous vein, the other surgicalinstrument 24 may hold the vein while the end effector of the instrumentis inserted into the patient.

[0140] The internal mammary artery (IMA) may be severed and moved by oneof the instruments to a graft location of the coronary artery. Thecoronary artery is severed to create an opening in the artery wall of asize that corresponds to the diameter of the IMA. The incision(s) may beperformed by a cutting tool that is coupled to one of the end effectorsand remotely manipulated through a master handle. The arteries areclamped to prevent a blood flow from the severed mammary and coronaryarteries. The surgeon manipulates the handle to move the IMA adjacent tothe opening of the coronary artery. Although grafting of the IMA isshown and described, it is to be understood that another vessel such asa severed saphaneous vein may be grafted to bypass a blockage in thecoronary artery.

[0141] Referring to FIGS. 10A-J, the surgeon moves the handle tomanipulate the instrument into driving the needle through the IMA andthe coronary artery. The surgeon then moves the surgical instrument tograb and pull the needle through the coronary and graft artery as shownin FIG. 10B. As shown in FIG. 10C, the surgical instruments are thenmanipulated to tie a suture at the heel of the graft artery. The needlecan then be removed from the chest cavity. As shown in FIGS. 10D-F, anew needle and thread can be inserted into the chest cavity to suturethe toe of the graft artery to the coronary artery. As shown in FIGS.10H-J, new needles can be inserted and the surgeon manipulates thehandles to create running sutures from the heel to the toe, and from thetoe to the heel. The scaled motion of the surgical instrument allows thesurgeon to accurately move the sutures about the chest cavity. Althougha specific graft sequence has been shown and described, it is to beunderstood that the arteries can be grafted with other techniques. Ingeneral the system of the present invention may be used to perform anyminimally invasive anastomostic procedure.

[0142] As disclosed hereinabove, the system may include a front loadingtool driver 84 which receives control signals from the controller 46 inresponse to movement of a master handle 50 or 52 and drives the tooldisposed at the end of a surgical instrument. Alternatively, a backloading tool driver 200 may be incorporated into the system 10 of thepresent invention, as depicted in FIGS. 11 and 11a. The back loadingtool driver 200 cooperates with a back loadable surgical instrument 202.The incorporation of such a back loading tool driver 200 and instrument202 expedites tool changing during procedures, as tools may be withdrawnfrom the tool driver 200 and replaced with other tools in a very simplefashion.

[0143] The back loading tool driver 200 is attached to a robotic armassembly 26 via a collar and holder as disclosed hereinabove. The backloading tool driver includes a sheath 204 having a proximal end 206 anda distal end 208. The sheath 204 may be formed of plastic or some otherwell-known material that is used in the construction of surgicalinstruments. The sheath 204 is essentially a hollow tube that fitsthrough the collar 85 and is tightened in place by the tightening toolthat is described in more detail hereinabove.

[0144] The back loadable surgical instrument 202 has a tool end 210 anda connecting end 212. A surgical tool 214, such as a grasper or someother tool that may be driven by a push/pull rod or cable system, or asurgical tool that does not require such a rod or cable, such as acoagulator, or harmonic scalpel is disposed at the tool end 210 of theinstrument 202.

[0145] A housing 216 is disposed at the connecting end 212 of theinstrument 202. The housing has a lever 218 disposed interiorly thehousing 216. The lever 218 has a pivot point 220 that is established byutilizing a pin passing through an associated aperture 222 in the lever.The pin may be attached to the interior wall 224 of the housing. Apush/pull cable or rod 226, that extends the length of the instrument202 is attached to the lever 218, such that movement of the lever 218about the pivot point 220 results in a linear movement of the cable orrod 226. Essentially the cable or rod 226 servers as a means 227 foractuating the tool 214 at the tool end 210 of the instrument 202. Thecable or rod 226 may be attached to the lever via a connection pin aswell. The lever 218 has a C-shape, wherein the ends of the lever 218protrude through two apertures 228, 230 in the housing 216. Theapertures 228, 230 are preferably surrounded by O-rings 232 the purposeof which shall be described in more detail hereinbelow.

[0146] The tool end 210 of the back loadable surgical instrument 202 isemplaced in the hollow tube of the back loading tool driver 200. Thetool 202 may be pushed through the tool driver until the tool end 210extends beyond the sheath 204. The O-rings 232 seat in associatedapertures 234, 236 in a housing 238 of the tool driver 200. The housingadditionally has an aperture 240 centrally formed therethrough, theaperture being coaxial with the interior of the hollow tube. In thisfashion, the surgical instrument 202 may be inserted into and throughthe tool driver 200. Each of the O-rings 232 snugly seats in itsassociated aperture in the housing 238 of the tool driver 200.

[0147] The housing 238 additionally includes a motor assembly 242 whichis depicted in FIG. 11a. The motor assembly 242 is attached to thehousing 238 and is held firmly in place therein. The motor assemblygenerally includes a motor 244 attached to a reducer 246. The motordrives a leaf 248 attached at the end thereof. The leaf 248 engages theends of the lever 218 such that rotational movement of the motor resultsin the movement of the lever 218 about the pivot point 220. This in turnresults in the lateral movement of the means 227 for actuating the tool214 at the tool end 210 of the instrument 202. The motor moves inresponse to movements at a control handle. Additionally, force sensors248, 250 may be attached at the ends of the leaf 248. As such, a forcefeedback system may be incorporated to sense the amount of forcenecessary to actuate the tool 214 at the tool end 210 of the instrument202. Alternatively, the motor 244 may have a force feedback device 252attached thereto, which can be used in a similar fashion.

[0148] One advantage of utilizing the back loading tool driver 200 isthat the sheath 204 always remains in the patient 12. As such, the toolsdo not have to be realigned, nor does the robotic arm assembly 26 whenreplacing or exchanging tools. The sheath 204 retains its positionrelative to the patient 12 whether or not a toll is placed therethrough.

[0149] The system 10 of the present invention may additionally besupplied with one or two additional degrees of freedom at the tip of aninstrument. For the purposes of example, two additional degrees offreedom will be disclosed; however it is to be appreciated that only onedegree of freedom may be included as well. To provide the additionaldegrees of freedom, and as depicted in FIGS. 13-16, an articulablesurgical instrument 300 may be incorporated into the present. Theinstrument 300 may be coupled to the arm assembly 26 via a collar andholder as disclosed hereinabove. In order to articulate the tip of thearticulable instrument 300 an articulating tool driver 500 must beemployed. The articulating tool driver 500 shall be described in moredetail hereinbelow. The master must have an additional two degrees offreedom added thereto to proved the controls for the articulation at thetip of the instrument 300. FIG. 25 depicts an alternative masterschematic that includes the two additional degrees of freedom. Asdisclosed hereinbelow, the two additional degrees of freedom are mappedto the articulable portion of the instrument 300. The two additionalaxes at the master are referred to as Jm6 and Jm7.

[0150] By incorporating the articulable instrument 300 and thearticulating tool driver 500 and the additional degrees of freedom atthe master, difficult maneuvers may be carried out in an easier fashion.

[0151] With reference to FIGS. 13-16, the articulable instrument 300generally includes an elongated rod 302, a sheath 304, and a tool 306.The tool can be a grasper, a cutting blade, a retractor, a stitchingdevice, or some other well-known tool used in minimally invasivesurgical procedures. FIGS. 27-30 show various tools that may be emplacedat the distal end of the articulable surgical instrument 300.

[0152] The instrument 300 includes an articulable portion 301 having aproximal portion 308, a pivot linkage 310 and a distal portion 212 eachof which will be discussed in more detail hereinbelow. Additionally, theinstrument 300 includes means 311 for articulating the articulableportion 301 of the instrument 300 with respect to the elongated rod 302.The inclusion of the articulable portion 301 provides two additionaldegrees of freedom at the instrument tip. It must also be appreciatedthat although the articulable portion 301 is described as including aproximal portion, a pivot linkage and a distal portion, there may beprovided a plurality of intermediate portions each mounted to each othervia a corresponding pivot linkage.

[0153] Disposed between and mounted to each of the respective proximalportion and distal portion and any intervening intermediate portions arepivot linkages 310. The pivot linkage 310 interengages with the proximaland distal portions of the articulable portion to provide articulationat the instrument tip. Essentially, the cooperation of the proximalportion, pivot linkage and distal portion serves as a universal joint.

[0154] The elongated rod 302 is preferably hollow and formed ofstainless steel or plastic or some other well-know material that issteralizable. Because the rod 302 is hollow, it encompasses and definesan interior 314. The elongated rod 302 additionally has a proximal end316 and a distal end 318. The distal end 318 of the elongated rod 302should not be confused with the distal portion 312 of the articulableportion 301 of the instrument 300.

[0155] The proximal portion 308 of the articulable portion 301 may beintegrally formed with the elongated rod 302 or it may be attachedthereto vie welding, glue or some other means well-known to the skilledartisan. It is preferable that the proximal portion 308 be integrallyformed with the elongated rod 302 to ensure sufficient stability anddurability of the instrument 300. The proximal portion 308 of thearticulable portion 301 comprises two fingers 320, 322 each of whichhave an aperture 324, 326 formed therethrough.

[0156] A pivot linkage 310 is mounted to the proximal portion 308 via aplurality of pins 328 that each pass through an associated aperture inan adjoining finger. The pivot linkage 310 is a generally flat disk 330having a central aperture 332 passing therethrough and four apertures334, 336, 338, 340 evenly spaced at the periphery of the disk 330.Additionally pins 328 are attached to and extend from the edge 342. Thepins 328 seat in the apertures of the associated fingers to provide thearticulability of the instrument 300. Five leads 350, 352, 354, 356, 358extend interiorly the hollow shaft. On lead 350 extends down the centerand passes through the center aperture 332 in the pivot linkage 310. Two352, 354 of the five leads extend down the hollow interior of theinstrument and are attached to the pivot linkage such that lineartension on one of the leads results in rotational movement of the pivotportion 301. These two leads 352, 354 attach to the pivot linkage at twoof the apertures formed therethrough. Additionally, they attach at thoseapertures that are adjacent to the pins that pass through the fingers ofthe proximal portion 308 of the articulable portion 301 of theinstrument 300. The other two leads 356, 358 pass through the two otherapertures in the pivot linkage and attach at the distal end of thearticulable portion 301. Movement of these two leads results in movementof the articulable portion 301 that is orthogonal to the movement whenthe two other leads 352, 354 are moved.

[0157] To articulate the instrument as a part of the present system, andas depicted in FIGS. 17-24, there is provided an articulating mechanism400. The articulating mechanism 400 generally comprises the articulatingtool driver 500, a sterile coupler 600, a translator 700 and thearticulable tool 300.

[0158] The translator is attached to the proximal end 316 of theinstrument 300. The instrument 300 may additionally have a removabletool 420 as shown in FIGS. 18-19. The removable tool 420 may be anytool, such as a cutter 422 that is attached to an elongated rod or cable424. At the end of the rod 246 there is disposed a flat section 428 withan aperture 430 formed therethrough. The flat section 428 seats into achannel 432 disposed at the end of a second cable or rod 434 thattravels down the elongated shaft of the instrument 300. The second cable434 has a channel 432 formed in the end thereof such that the flatsection 428 seats in the channel 432. At least one spring biased detent436 seats in the aperture 430 disposed through the flat section 428.This connects the tool 420 to the rest of the instrument 300. As such,tools may be exchanged at the tip of the instrument without having toremove the instrument from the system 10 every time a new tool isrequired.

[0159] The tool 300 is attached to the translator 700 and essentially isintegrally formed therewith. The articulating mechanism 400 is attachedto the robotic arm assembly 26 via the collar 85 as is disclosedhereinabove. The collar 85 fits about the shaft 302 of the instrument300.

[0160] The translator 700 has a proximal end 702 and a distal end 704.The distal end 704 of the translator 700 has a cross sectional shapethat is substantially similar to the cross sectional shape of theelongated rod 302 of the instrument 300. Additionally, the translator700 has a hollow interior 706. The center rod 350 extends through thehollow interior 706 of the translator 700 and emerges at the proximalend 702 thereof. Two of the leads 352, 354 terminate interiorly thetranslator at two shoulders 708, 710 that are attached to a first hollowtube 712 through which the center lead 350 extends. The first hollowtube 712 may be formed of some strong durable material such as stainlesssteel, steel, hard plastic or the like.

[0161] The first hollow tube 712 is mounted to a bearing 714 such thatit may be rotated. Rotation of the first hollow tube 712 results in thelinear motion of the leads 352, 254 and the articulation of thearticulable portion 301 of the instrument 300 in one plane of motion.

[0162] A second hollow tube 716 has a pair of shoulders 718, 719extending therefrom. Two leads 356, 358 attach to one each of theshoulders 718, 719. The hollow tube 716 is disposed within a bearingassembly 720 such that it may be rotated. Again, rotation of the secondhollow tube 716 results in linear movement of the leads 356, 358 whicharticulates the articulable portion 301 of the instrument 300 in a planeorthogonal the plane of motion established through the rotation of thefirst hollow tube. It is to be appreciated that the second hollow tube714 radially surrounds the first hollow tube 712. The translator 700additionally includes a quick disconnect 722 comprising a pin 724disposed at the end of a spring biased lever 726 which providesremovable attachment of the translator 700 to the sterile coupler 600.Both of the hollow tubes 712 and 716 may have notches 750 formed thereinat their ends. The notches serve as a means 752 for interconnecting eachof the tubes to the sterile coupler 600 which will be discussed infurther detail hereinbelow.

[0163] The translator 700 is removably attached to the sterile coupler600 via the quick disconnect 722. Because the articulable tool driver500 is not easily sterilized, it is advantageous to include a sterilecoupler 600 so that instruments may be exchanged without having tosterilize the articulable tool driver 500. Additionally, the coupler 600provides a means by which the translator 700 may be attached to the tooldriver 500 while the tool driver is enclosed in a drape 125 such as thatdepicted in FIG. 26. The translator 600 has a housing 610. Preferablythe housing and the components of the coupler 600 are formed of someeasily steralizable mater such as stainless steel, plastics or otherwell-known sterilizable materials. The housing 610 has a substantiallyhollow interior 612 and open ends 614 and 616. Two hollow tubes 618 and620 are rotatively disposed within the housing 610. To effectuate therotation of each of the tubes 618 and 620, bearings 622 and 624 aredisposed about each of the tubes. Each of the tubes has notches 626formed in the ends thereof so effectuate the attachment of thetranslator 700 to the coupler 600 at one end. And to effectuate theattachment of the coupler 600 to the articulable tool driver 500 at theother end thereof.

[0164] The pin 724 on the translator may seat in a notch 628 to attachthe translator 700 to the coupler 600. Additionally, the coupler 600 mayinclude a pin 630 attached to a spring biased pivot 632 to effectuateattachment of the coupler to the driver 500. The coupler 600additionally includes a center section 634 that slidably receives theend 351 of the center cable or rod 350. The end 351 may include a tipwith a circumferential groove 353 disposed thereabout. The tip seats ina recess 636 formed in the center section 634 and is removably locked inplace by at least one spring biased detent 638. A tip 640, which issubstantially similar to the tip containing the circumferential groove353 is disposed adjacent the recess 636 and serves to attach the cablecenter cable 350 to the articulable tool driver 500, which will bediscussed in further detail hereinbelow.

[0165] The center section 634 is intended to laterally slide within theinnermost tube 618. To effectuate such a sliding motion, a linearbearing may be disposed about the center section interiorly of theinnermost tube. Alternatively, the center section 634 may be formed of abearing material that provides smooth sliding within the innermost tube618.

[0166] The coupler 600 is removably attached to the articulable tooldriver 500. It is intended that the articulable tool driver be enclosedby a drape 125. The articulable tool driver 500 includes a substantiallyhollow housing 502 having a closed first end 504 and a substantiallyopen second end 504. Securely disposed interiorly the housing 502 is agripper motor 506, and a pair of wrist motors 508 and 510. Each of themotors are in electrical connection with the controller 46.Alternatively, the motors may receive signals from the controller via atransmitter/receiver system where such systems are well known. It is theapplication of such a transmitter/receiver system to the presentinvention that is new. The gripper motor 506 is attached to a load nut510 that surrounds a load screw 512. The motor 506 receives the controlsignals and turns in response thereto. The load nut 510 turns whichlaterally moves the load screw 512. The load screw 512 is attached to aload cell 514 which may be employed to measure the force required tolaterally move the cable 350 which is attached vie the coupler 600 tothe gripper motor 506. This may be used in a force feedback system thatmay be incorporated in the system 10 of the present invention. A rod 516having a channel 518 formed at the end thereof is attached to the loadcell 514. As such, the rod 516 moves in a linear fashion. The tip 640 ofthe coupler 600 seats in the channel 518 and is removably held in placeby at least one spring biased detent or some other similar attachmentmechanism 520. Therefore, if a surgeon at a master handle actuates thegrippers, the gripper motor 506 turns, thus laterally moving the rod516, and in turn the center cable 350 which opens and closes thegrippers at the tool accordingly. Of course, the action at the tool willdepend upon the type of tool disposed thereat. For example, if astapling tool is disposed at the end of the surgical instrument 300 thena stapling action would take place.

[0167] If a master handle 50 or 52 is turned about axes J6 or J7 thenone of the two wrist motors 510, 508 corresponding to the requiredmotion turns. Each of the motors 508, 510 are attached to acorresponding gear 522, 524. Each of the gears 522, 524 engage acorresponding slotted section 530, 532 of an associated hollow tube 526,528 to turn the associated tube radially about its longitudinal axis.Each of the tubes 526, 528 include notched ends 534, 536 to engage thenotched ends of corresponding hollow tubes of the coupler 600. It is tobe appreciated that each of the hollow tubes 526, 528, 618 and 620 areall coaxial. Additionally, bearings may be emplaced intermediate each ofthe tubes 526 and 528 to provide easy independent rotatability of theindividual tubes.

[0168] When the tubes 526, 528 are rotated, they rotate the tubes in thecoupler which rotates the tubes in the translator. This results in thearticulation at the tip of the surgical instrument 300. Moreparticularly, this results in the articulation of the articulableportion of the surgical instrument 300. Additionally, whether the frontloading tool driver, the back loading tool driver, or the articulabletool driver are employed, surgical instruments may be easily exchanged.

[0169] As such, a cutting blade 800 may be exchanged for a grasper, anda grasper may be exchanged for a stapler 810. Essentially, such a systemsimplifies the performance of minimally invasive surgical procedureswhere the procedures include the step of changing one tool for another.And because the system allows articulation at the tip of certaininstruments, the articulation mechanism may be used to articulate suchstapling, or cutting instruments that incorporate the articulableportion as disclosed hereinabove.

[0170] Additionally, the instrument may not be an articulableinstrument, but the articulating mechanism can be used to control otherfunctions, such as stapling. FIG. 27 depicts a stapling instrument 810attached to the robotic arm assembly via the collar 85 and holder 86.The lead that is generally use for the grasping tool, may be used toeffectuate the stapling mechanism. Endoscopic staplers are generallywell known in the art, however, it is heretofore to known to use astapler that is attached to a robotic arm as is disclosed herein.

[0171] Additionally, a cutting blade, such as that depicted in FIG. 28may be employed in the system of the present invention. The cuttingblade 800 is attached to the robotic arm assembly 26 via the collar 85and holder 86. The cutting blade does not require a lead such as thatrequired by the grasper or the stapler; however, the cutting tool, maybe articulated via the articulating mechanism that has been disclosedhereinabove.

[0172] A cauterizer or coagulator may additionally be attached to therobotic arm assembly 26 via the collar 85 and holder. Cauterizers andcoagulators are well known and the cauterizing tool may be attached atthe end of an articulable instrument as disclosed hereinabove. By usinga variety of tools in predetermined sequences, various procedures may becarried out. It is generally preferable to be able to change instrumentsbecause many procedures require such.

[0173] While certain exemplary embodiments have been described and shownin the accompanying drawings, it is to be understood that suchembodiments are merely illustrative of and not restrictive on the broadinvention, and that this invention not be limited to the specificconstructions and arrangements shown and described, since various othermodifications may occur to those ordinarily skilled in the art.

What is claimed is:
 1. A medical robotic system, comprising: a roboticarm; a coupler that pivotally attaches to the arm; an endoscopicsurgical instrument that is held by said coupler; and a controllerhaving a handle, the controller in electrical communication with therobotic arm; and wherein movement at the controller produces aproportional movement of the robotic arm and surgical instrument.
 2. Thesystem of claim 1 wherein said coupler removably attaches to saidrobotic arm.
 3. The system of claim 1 wherein said endoscopic surgicalinstrument is an articulable endoscopic surgical instrument.
 4. Thesystem of claim 1 wherein the articulable surgical instrument comprisesa base, a pivot linkage, and a distal end.
 5. The system of claim 4wherein a movement at the controller results in corresponding movementof the distal end of the articulable surgical instrument relative to thebase of the articulable surgical instrument.
 6. The system of claim 1wherein the coupler has an aperture formed therethrough.
 7. A method foroperating a surgical robotic system for performing a surgical procedureon a patient, the method comprising: 1) providing a first articulatearm, a controller and an input device which receives input commands, thefirst articulate arm in electrical communication with the controller andthe controller in electrical communication with the input device; 2)cutting at least one incision into the patient; 3) attaching a surgicalinstrument to the first articulate arm; 4) inserting said surgicalinstrument into the patient through the at least one incision; 5)generating input commands to move said surgical instrument in accordancewith the procedure being performed wherein said robotic arm moves saidsurgical instrument in accordance with the input commands; and 6)removing the surgical instrument from the patient.
 8. The method ofclaim 7 wherein after removing the surgical instrument from the patientfurther comprises the steps of: 1) replacing the surgical instrumentwith a different surgical instrument; 2) inserting said differentsurgical instrument into the patient; 3) generating input commands tomove the different surgical instrument in accordance with the procedurebeing performed wherein said robotic arm moves the different surgicalinstrument in accordance with the input commands; and 4) removing thedifferent surgical instrument from the patient.
 9. The method of claim 7wherein said surgical instrument is a grasper.
 10. The method of claim 7wherein the surgical instrument is a stapler.
 11. The method of claim 7wherein the surgical instrument is a cauterizer.
 12. The method of claim7 wherein the surgical instrument is a cutting blade.
 13. The system ofclaim 5 wherein the tool attached at the distal end of the articulablesurgical instrument is a stapler.
 14. The system of claim 5 wherein thetool attached at the distal end of the articulable surgical instrumentis a cauterizer.
 15. The method of claim 7 wherein the step of attachinga surgical instrument to the collar by passing the instrument tipthrough the collar.